Absorbent article having flaps and zones of differential extensibility

ABSTRACT

An absorbent article, such as a sanitary napkin, having flaps and zones of differential extensibility for relieving the stresses that develop in the flaps when the flaps are folded down along the edges of crotch of the wearer&#39;s undergarments is provided.

This is a continuation of application Ser. No. 07/769,891, filed on Oct.1, 1991, now abandoned.

FIELD OF THE INVENTION

The present invention relates to absorbent articles such as sanitarynapkins, adult incontinence devices, and the like. Still moreparticularly, the present invention concerns absorbent articles havingflaps and zones of differential extensibility for relieving the stressesthat develop in the flaps when the flaps are folded down and under awearer's undergarment.

BACKGROUND OF THE INVENTION

All manner and variety of absorbent articles configured for theabsorption of body fluids such as menses, urine, and feces are, ofcourse, well known. Absorbent articles, particularly sanitary napkins,having wings or flaps are disclosed in the literature and are availablein the marketplace.

Generally, the flaps extend laterally from a central absorbent means andare intended to be folded around the edges of the wearer's panties inthe crotch region. Thus, the flaps are disposed between the edges of thewearer's panties in the crotch region and the wearer's thighs. Commonly,the flaps are provided with an attachment means for affixing the flapsto the underside of the wearer's panties.

The flaps serve at least two purposes. First, the flaps prevent exudateswhich otherwise would soil the edges of the wearer's panties from doingsuch. Second, the flaps help stabilize the napkin from shifting out ofplace, especially when the flaps are affixed to the underside of thepanties.

Sanitary napkins having flaps of the various types are disclosed in U.S.Pat. No. 4,687,478, entitled "Shaped Sanitary Napkin With Flaps", whichissued to Van Tilburg on Aug. 18, 1987, U.S. Pat. No. 4,608,047,entitled "Sanitary Napkin Attachment Means", which issued to Mattinglyon Aug. 26, 1986, U.S. Pat. No.4,589,876, entitled "Sanitary Napkin",which issued to Van Tilburg on May 20, 1986, U.S. Pat. No. 4,285,343,entitled "Sanitary Napkin", which issued to McNair on Aug. 25, 1981,U.S. Pat. No. 3,397,697, entitled "Disposable Sanitary Shield ForUndergarments", which issued to Rickard on Aug. 20, 1968, and U.S. Pat.No. 2,787,271, entitled "Sanitary Napkin", which issued to Clark on Apr.2, 1957.

While sanitary napkins having flaps are commonly viewed as providingbetter protection against soiling as compared to sanitary napkinswithout flaps, the flapped napkins commonly experience problems thatkeep them from being optimally effective. These problems generallyresult from the stresses exerted on such flaps when the sanitary napkinsare worn.

When the flaps are folded down along the edges of the wearer's panties,stresses are created in the flaps. The stresses are especially highalong the fold line at the edges of the wearer's panties where the flapsare bent from the bodyside of the panty to the underside of the panty.These stresses are caused by fitting a flap around the curved outline ofa panty crotch. These stresses are magnified when a wearer sits orcrouches because the edges of the panties are pulled outward against theflaps thus increasing the forces against this fold line. When thestresses become too high, the flaps may become detached from the pantyand some portion of the aforementioned benefits of the flaps may belost. In addition, even if the stresses are not sufficient to detach theflaps, they may still be sufficient to cause the flaps to bunchlongitudinally inward. This effectively reduces the size of the flapsand the area of the wearer's undergarments that the flaps are able tocover. Thus, there is a commercial need for a way of eliminating or atleast reducing the stresses that develop in the flaps when folded, so asto prevent them from becoming detached from the wearer's panties andlosing ability to cover a given area of the panties.

A number of variations on the types of flaps described above have beenpresented in an attempt to solve various problems. U.S. Pat. No.4,900,320 issued to McCoy on Feb. 13, 1990, discloses a sanitary napkinhaving flaps affixed at points inward from the longitudinal edge of thenapkin. U.S. Pat. No. 4,911,701 issued to Mavinkurve on Mar. 27, 1990,discloses a sanitary napkin having elastic means for providing greaterconvex shape to the body-facing portion of the central absorbent and forenabling adhesive-free placement of the flaps of the napkin. U.S. Pat.No. 4,940,462 issued to Salerno on Jul. 10, 1990, discloses a sanitarynapkin with longitudinally expandable flaps. A sanitary napkin havingflaps with stress relief means in the form of a notch or a slit isdescribed in U.S. Pat. No. 4,917,697 which issued to Osborn, III, et al.on Apr. 17, 1990. Although this latter sanitary napkin works quite well,the search for sanitary napkins having improved flaps has continued.

The stresses described above can also unduly limit the size of the flapsused with an absorbent article since the stresses are typically greaterin products having large flaps (that is flaps having a relatively largelongitudinal dimension). There is, thus, also a need for an improvedstress relief means for relieving the stresses that develop in theflaps, that does not limit the size of the flaps that can be used.

Therefore, it is an object of the present invention to provide anabsorbent article, such as a sanitary napkin, having flaps and zones ofdifferential extensibility for relieving the stresses that develop inthe flaps when they are folded down along the edges of the crotch of thewearer's undergarments and affixed to the underside of theundergarments.

It is an additional object of the present invention to provide anabsorbent article having flaps and zones of differential extensibilitythat allow larger flaps to be used on the absorbent article, than thoseof prior products.

These and other objects of the present invention will be more readilyapparent when considered in reference to the following description andwhen taken in conjunction with the accompanying drawings.

SUMMARY OF THE INVENTION

In accordance with the present invention, an absorbent article, such asa sanitary napkin, having flaps and zones of differential extensibilityfor relieving the stresses that develop in the flaps when the flaps arefolded down along the edges of the wearer's panties in the crotch, isprovided.

The sanitary napkin has a principal longitudinal centerline and aprincipal transverse centerline. The sanitary napkin comprises a mainbody portion and a pair of flaps associated with the main body portion.The main body portion of the sanitary napkin comprises a liquid pervioustopsheet, a liquid impervious backsheet joined to the topsheet, anabsorbent core positioned between the topsheet and the backsheet. Themain body portion has two spaced apart longitudinal edges and two spacedapart transverse edges.

The flaps extend laterally outward from the main body portion. The flapsare associated with the main body portion at a juncture along thelongitudinal edges of the main body portion. The flaps are divided intoa front half and a back half by a flap transverse centerline. Theabsorbent article has two corner regions located adjacent the area ofthe ends of the junctures. One corner region is located adjacent thearea of the juncture in each direction remote from the principaltransverse centerline. The sanitary napkin comprises zones ofdifferential extensibility which allow the corner regions to extendtransversely outward to a greater degree than the portions of thesanitary napkin located along the flap transverse centerline. The zonesof differential extensibility provide a means for the relief of stressesin the flaps of the sanitary napkin when the sanitary napkin is placedin the wearer's undergarments. A nonlimiting number of types of zones ofdifferential extensibility are disclosed.

BRIEF DESCRIPTION OF THE DRAWINGS

FIG. 1 is a top plan view of a preferred sanitary napkin embodiment ofthe present invention.

FIG. 1A is a lateral cross-sectional view taken along line 1A--1A ofFIG. 1 through the corner region of one of the flaps of the sanitarynapkin.

FIG. 1B is a lateral cross-sectional view taken along line 1B--1B ofFIG. 1 through the center portion of one of the flaps.

FIG. 2 is a top plan view of a sanitary napkin embodiment of the presentinvention having flaps with an alternatively preferred type of zones ofdifferential extensibility.

FIG. 2A is a lateral cross-sectional view taken along line 2A--2A ofFIG. 2 through one of the flaps of the sanitary napkin.

FIG. 3 is a perspective view of the crotch portion of a women's panties.

FIG. 4 is the same perspective view of the women's panties shown in FIG.3 with the sanitary napkin embodiment of FIG. 1 being placed therein foruse.

FIG. 5 is a top plan view of an alternatively preferred sanitary napkinembodiment of the present invention.

FIG. 6 is a cross-sectional view of the sanitary napkin embodiment shownin FIG. 5 taken along line 6--6 of FIG. 5.

FIG. 7 is a cross-sectional view of another sanitary napkin embodimenttaken from an angle similar to that of FIG. 6 having a pleat joined toits backsheet.

FIG. 8 is plan view of a sanitary napkin embodiment showing a curvedpattern of joining the flap to the main body portion of the sanitarynapkin.

FIG. 8A is plan view of another sanitary napkin embodiment showing acurved pattern of joining the flap to the main body portion of thesanitary napkin.

FIG. 8B is a plan view of a method of making flaps for the embodimentshown in FIG. 8A.

FIGS. 8C-8E are various top and bottom plan views of still anotherembodiment of a sanitary napkin in which the flaps are joined to themain body portion of the sanitary napkin along a curved juncture.

FIG. 9 is a top plan view of another embodiment of a sanitary napkin inwhich the main body portion of the sanitary napkin is folded.

FIG. 10 is a simplified cross-sectional view of the sanitary napkinembodiment shown in FIG. 9 taken along line 10--10 of FIG. 9.

FIG. 11 is a bottom plan view of the sanitary napkin embodiment shown inFIG. 9.

FIG. 12 is a simplified transverse cross-sectional view of anotheralternatively preferred sanitary napkin embodiment of the presentinvention in which the main body portion is folded only once.

FIG. 13 is a simplified transverse cross-sectional view of anotheralternatively preferred sanitary napkin embodiment of the presentinvention in which the main body portion contains multiple folds.

FIG. 14 is an exploded perspective view showing the assembly of asanitary napkin which contains a preferred absorbent core and pantyfastening adhesive pattern for use in the present invention (but whichdoes not include flaps and the zones of differential extensibility ofthe present invention).

FIG. 15 is a diagram which illustrates some of the terms and conceptsdescribed in Table 1.

FIG. 16 is a top plan view of a sanitary napkin having flaps providedwith an optional barrier feature.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

The present invention relates to absorbent articles, such as sanitarynapkins. More particularly, the present invention relates to absorbentarticles having flaps and zones of differential extensibility forrelieving the stresses that develop in the flaps when they are foldeddown along the edges of the crotch of the, wearer's undergarments andattached to the underside of the undergarments.

The term "absorbent article", as used herein, refers to articles whichabsorb and contain body exudates. More specifically, the term refers toarticles which are placed against or in proximity to the body of thewearer to absorb and contain the various exudates discharged from thebody. The term "absorbent article" is intended to include sanitarynapkins, pantiliners, and incontinent pads (and other articles worn inthe crotch region of a garment). The term "disposable" refers toarticles which are intended to be discarded after a single use andpreferably recycled, composted, or otherwise disposed of in anenvironmentally compatible manner. (That is, they are not intended to belaundered or otherwise restored or reused as an absorbent article.) Inthe preferred embodiment illustrated, the absorbent article is asanitary napkin designated 20.

The term "sanitary napkin", as used herein, refers to an article whichis worn by females adjacent to the pudendal region that is intended toabsorb and contain the various exudates which are discharged from thebody (e.g., blood, menses, and urine). The present invention, however,is not limited to the particular types or configurations of absorbentarticles shown in the drawings.

A preferred embodiment of a sanitary napkin 20 of the present inventionis shown in FIG. 1. As shown in FIG. 1, the sanitary napkin 20 basicallycomprises an absorbent means represented by central absorbent pad (or"main body portion") 22, and two flaps 24. (In the discussion thatfollows, unless otherwise noted, the sanitary napkin described hereinwill have two flaps. While it is not necessary that the napkin have twoflaps, two flaps are preferred over one flap. Also, while it is notnecessary that the flaps be mirror images of one another, theypreferably are. Thus, the description of one flap will be a descriptionof the other, and, for clarity, discussion of the second flap may beomitted.)

The sanitary napkin 20 has two centerlines, a principal longitudinalcenterline l and a principal transverse centerline t. The term"longitudinal", as used herein, refers to a line, axis or direction inthe plane of the sanitary napkin 20 that is generally aligned with(e.g., approximately parallel to) a vertical plane which bisects astanding wearer into left and right body halves when the sanitary napkin20 is worn. The terms "transverse" or "lateral" used herein, areinterchangeable, and refer to a line, axis or direction which lieswithin the plane of the sanitary napkin 20 that is generallyperpendicular to the longitudinal direction.

The sanitary napkin 20 is comprised of a topsheet 40, a backsheet 42, anabsorbent core 44, and a pair of flaps 24. At least a part of thetopsheet 40, backsheet 42, and absorbent core 44 comprise the main bodyportion 22. The flaps 24 shown in FIGS. 1 and 1A are comprised ofseparate pieces of material which are attached to the main body portion22. (In alternative embodiments, such as those shown in U.S. Pat. No.4,917,697 issued to Osborn, the flaps 24 may be integral with the mainbody portion 22. In such a case, the topsheet 40 may form one surface ofboth the flaps 24 and the main body portion 22, and the backsheet 42 mayform the other surface of the same. In addition, the absorbent materialof the sanitary napkin 20 may extend into the flaps 24 to form a flapabsorbent core, as described in greater detail in U.S. Pat. No.4,917,697.)

The flaps 24 are each associated with main body portion 22 along ajuncture. This is typically a longitudinally-oriented (or"longitudinal") juncture, such as lines of juncture 30. As used herein,the terms "juncture" (or "line of juncture") refer to regions where theflaps 24 extend from or are joined to the main body portion 22. Theseregions can be any of various curved or straight lines, but they are notlimited to lines. Thus, these regions can comprise flanges, strips,intermittent lines, and the like. In the embodiment illustrated in FIG.1, line of juncture 30 is a relatively straight line.

The flaps 24 have a proximal edge 32 adjacent the line of juncture. Adistal edge (or "free end") 34 is remote from the line of juncture 30.As shown in FIG. 1, each flap 24 is divided into a front half 26, and aback half 28 by a flap transverse centerline t₁. The flap transversecenterline t₁ may coincide with the principal transverse centerline t ofthe sanitary napkin, but this is not absolutely required. The flaptransverse centerline t₁ extends through the principal longitudinalcenterline l to divide the sanitary napkin into four quarters A, B, C,and D.

The quarters comprise a first portion or zone (such as A₁, B₁, C₁, andD₁) adjacent at least a portion of the principal longitudinal centerlinel and the flap transverse centerline t₁. A second portion or zone (A₂,B₂, C₂, and D₂) is outboard of and complementary with the first portion.(The terms "outboard" or "outward", as used herein, mean generallyspaced in a direction away from these centerlines. The term"complementary", as used herein, means that the first and secondportions form an entire quarter.)

The sanitary napkin 20 has at least one zone of differentialextensibility (or "zone of extensibility", or simply "zone") 50.Preferably, as shown in FIG. 1, the sanitary napkin 20 has four zones ofdifferential extensibility 50, one in each quarter of the sanitarynapkin 20. The zones of differential extensibility 50 relieve thestresses which develop in the flaps 24 when they are folded around apanty crotch. Since the zones of differential extensibility 50 relievestresses in the flaps, they may be referred to herein as a type of"stress relief means".

The term "zone of differential extensibility", as used herein, refers toa portion of the sanitary napkin 20 which is capable of extending adiffering amount (preferably a greater amount), than surroundingportions of the sanitary napkin 20. These "surrounding portions" of thesanitary napkin comprise the first portions of the quarters. The zonesof differential extensibility 50, thus, comprise the second portions ofeach quarter.

The zones of differential extensibility 50 are preferably primarilyextensible in a greater amount generally outward in the transversedirection. This is generally in the direction of the arrows shown inFIG. 1. As used herein, "generally in the transverse direction" meansthat the extensibility has a transverse component. All of the extension,however, need not be exactly parallel to the principal transversecenterline of the sanitary napkin. The extensibility is preferablyoriented more in the transverse direction than in the longitudinaldirection.

The zone(s) of differential extensibility 50 can comprise any structurecapable of extending a greater amount in the transverse direction thanthe surrounding portions of the sanitary napkin. The differentialextensibility referred to herein, however, must be elasticless. That is,it must be accomplished without the use of separate elastic pieces,strands, or materials to contract one or more portions of the sanitarynapkin. The zones of differential extensibility must also beaccomplished without slitting or notching portions of the sanitarynapkin that cover the wearer's undergarments. This will have theadvantage that exudates will not be able to travel through the slits ornotches to soil the wearer's undergarments.

Suitable structures for the zones of differential extensibility 50include, but are not limited to zones of material that are mechanicallystrained, corrugated, "ring rolled", folded, pleated, or joined along acurved juncture. These structures (although sometimes shown only asbeing part of the flaps 24), can comprise portions of the main bodyportion 22, portions of the flaps 24, or both. They can be integralparts of these components of the sanitary napkin, or separate elements,such as pieces of material, joined to the sanitary napkin.

The zones of differential extensibility 50 are more specifically locatedin the corner regions 52 of the sanitary napkin 20. (Thus, the secondportions A₂, B₂, C₂, and D₂ of the quarters preferably comprise thecorner regions 52 of the sanitary napkin 20.) The sanitary napkin 20preferably has four corner regions 52 (two by each flap, and one in eachquarter).

The term "corner regions" 52, as used herein, refers to portions of thesanitary napkin 20 that are generally located along or adjacent aportion of the longitudinal juncture of each flap 24. The corner regions52 for each flap 24 are located in two areas in the regions of the ends30a and 30b of each juncture 30. One corner region 52 is locatedadjacent the longitudinal juncture 30 in the front half 26 of the flap24. The other is adjacent the longitudinal juncture 30 in the back half28 of the flap 24. The corner regions 52 are preferably at leastpartially disposed longitudinally away from the flap transversecenterline t₁ in each direction. (Thus, the corner regions 52 may bedescribed as being longitudinally "remote" from the flap transversecenterline t₁.)

In the most preferred case (as will be subsequently described in greaterdetail), the zones of differential extensibility 50 are located along aportion of the fold line where the flaps 24 are folded around thewearer's panty crotch. The fold line will typically be located along oradjacent the longitudinal juncture 30 of each flap 24. Since the terms"portions", "zones", and "regions", as used herein, refer to generalareas, the zones of differential extensibility 50 and the corner regions52 are, thus, not limited to points which lie precisely on the lines ofjuncture 30. Typically, they will include both those points which lie onthe lines of juncture 30 as well as the surrounding areas of thesanitary napkin 20 (which include the aforementioned fold lines). Thelongitudinal junctures, thus, typically serve as good approximations forthe location of the zones of differential extensibility 50.

The corner regions 52 are designated as such because they typicallyinclude the "corners" formed along the periphery 23 of the sanitarynapkin 20. The "corners" occur where the edges 35 of the flaps 24intersect with the longitudinal side edges 22a of the main body portion22 when the sanitary napkin 20 is shown in a plan view. It is notnecessary for there to be a sharp angle formed at the intersection ofthese edges, or for lines of demarcation to designate the same, however.(Another way to describe the corner regions 52 is with reference to U.S.Pat. No. 4,917,697 issued to Osborn, III, et al. The corner regions 52described herein are typically comprised at least of those areas shownas having slits or notches in the Osborn, et al. patent. (Forsimplicity, these areas may be referred to herein as "notch regions").However, the corner regions 52 in the present invention preferablyencompass a larger area than the slits or notches shown in the Osbornpatent.)

The portions of the flaps 24 in the corner regions 52 of the sanitarynapkin 20 may be referred to as the "corner regions of the flaps" or"flap corner regions". These may be separately designated 52' althoughthey are still considered to comprise the corner regions 52, per se.

FIGS. 1 and 1A show an embodiment of the present invention which has onepreferred type of zones of differential extensibility 50. In theembodiment shown in FIGS. 1 and 1A, the zones of differentialextensibility 50 comprise portions of the sanitary napkin 20 that haveslack provided therein. These portions of the sanitary napkin 20comprise at least the flap corner regions 52'.

The slack is provided to the sanitary napkin 20 in the embodiment shownin Figures 1 and 1A by pre-stretching (or "pre-straining") the cornerregions of the flaps 52'. This can be accomplished by heating and thenstretching the flap corner regions generally in the transversedirection. This heating and stretching increases the size of the flapcorner regions 52'. Thus, when the sanitary napkin is laid out as shownin FIGS. 1 and 1A with the flaps 24 extended, there is excess materialin the flap corner regions 52'. This excess material (as described ingreater detail below) allows the flaps 24 to be folded around the crotchof the wearer's panties without stresses being created in the cornerregions 52.

Any known method of stretching materials can be used to pre-stretch thecorner regions 52. (It is expressly not admitted, however, that the useof zones of differential extensibility 50 in the manner of the presentinvention is known.) Any suitable process that stretches the material ofthe corner regions 52 beyond their point of plastic deformation topermanently deform (or elongate) the corner regions 52 can be used. Forinstance, it is not necessary for the corner regions 52 to be heatedprior to stretching the same. Heating may make the stretching easier,however. In addition to pre-stretching, a number of alternative ways ofproviding zones of differential extensibility are described in greaterdetail below in conjunction with the embodiments shown in the remainingdrawing figures.

The individual components of the sanitary napkin 20 will first be lookedat in greater detail.

The topsheet 40 is liquid permeable and when the sanitary napkin 20 isin use, the topsheet 40 is in close proximity to the skin of the user.The topsheet 40 is compliant, soft feeling, and non-irritating to theuser's skin. It can be made from any of the materials conventional forthis type of use. Nonlimiting examples of suitable materials that can beused as topsheet 40 are woven and nonwoven polyester, polypropylene,nylon, and rayon and formed thermoplastic films, with formed films beingpreferred.

Suitable formed films are described in U.S. Pat. No. 3,929,135, entitled"Absorptive Structure Having Tapered Capillaries", which issued toThompson on Dec. 30, 1975, U.S. Pat. No. 4,324,426, entitled "DisposableAbsorbent Article Having A Stain-Resistant Topsheet", which issued toMullane and Smith on Apr. 13, 1982, U.S. Pat. No. 4,342,314, entitled"Resilient Plastic Web Exhibiting Fiber-Like Properties", which issuedto Radel and Thompson on Aug. 3, 1982, and U.S. Pat. No. 4,463,045,entitled "Macroscopically Expanded Three-Dimensional Plastic WebExhibiting Non-Glossy Visible Surface and Cloth-Like TactileImpression", which issued to Ahr, Louis, Mullane, and Ouellette on Jul.31, 1984. Formed films are preferred for topsheet 40 because they arepervious to liquids and yet non-absorbent. Thus, the surface of theformed film which is in contact with the body remains dry and is morecomfortable to the wearer.

In one particularly preferred embodiment (shown in FIG. 14 without thezones of differential extensibility of the present invention) thesanitary napkin 20 is comprised of components that are extensible (i.e.,capable of stretching, particularly in the longitudinal direction) whenthe sanitary napkin is worn. Preferably, the sanitary napkin 20 iscapable of elongating between about 15% and about 40% of its unstretchedlength. This extensibility provides better in-use fit, comfort, anddecreased staining. In other embodiments, only limited portions of thecomponents of the sanitary napkin 20 are capable of stretching.

A particularly preferred topsheet 40 for use in such an embodiment isone which is made in accordance with U.S. Pat. No. 4,463,045 and ringrolled to provide it with a degree of longitudinal extensibility.Suitable processes for ring rolling or "pre-corrugating" are describedin U.S. Pat. No. 4,107,364 issued to Sisson on Aug. 15, 1978, U.S. Pat.No. 4,834,741 issued to Sabee on May 30, 1989 and in co-pending,commonly assigned U.S. patent application Ser. No. 07/662,536 entitled"Improved Method And Apparatus For Incrementally Stretching A ZeroStrain Stretch Laminate Web To Impart Elasticity Thereto" filed byGerald M. Weber et al. on Feb. 28, 1991, U.S. patent application Ser.No. 07/662,537 entitled "Improved Method and Apparatus For IncrementallyStretching Zero Strain Stretch Laminate Web In A Non-Uniform Manner ToImpart A Varying Degree of Elasticity Thereto" filed by Kenneth B. Buellet al. on Feb. 28, 1991, and U.S. patent application Ser. No. 07/662,543entitled "Improved Method And Apparatus For Sequentially Stretching ZeroStrain Stretch Laminate Web To Impart Elasticity Thereto WithoutRupturing The Web" filed by Gerald M. Weber et al. on Feb. 28, 1991. Thefold lines in the corrugations of the topsheet should run in thetransverse direction so the topsheet is longitudinally extensible.

Such a topsheet is described in greater detail in the following patentapplications which were filed on Jun. 23, 1991: U.S. patent applicationSer. No. 07/734,404 entitled "Absorbent Articles, EspeciallyCatamenials, Having Improved Fluid Directionality, Comfort and Fit"filed in the names of Thompson, et al.; U.S. patent application Ser. No.07/734,392 entitled "Fluid Handling Structure for Use in AbsorbentArticles" filed in the names of Thompson, et al.; and, U.S. patentapplication Ser. No. 07/734,405 entitled "Absorbent Core for Use inCatamenial Products" filed in the names of Buenger, et al. These patentapplications may be referred to collectively as the "Capillary ChannelFiber" patent applications.

In addition, in preferred embodiments of the present invention, at leasta portion of the outer surface 40a of the topsheet 40 is treated with asurfactant. It is preferred that the surfactant be substantially evenlyand completely distributed across at least the portion of the outersurface 40a of topsheet 40 that overlays the main body portion 22. Thiscan be accomplished by any of the common techniques well known to thoseskilled in the art. For example, the surfactant can be applied totopsheet 40 by spraying, by padding, or by the use of transfer rolls.

Treating the outer surface 40a of the topsheet 40 with a surfactantrenders the surface of the topsheet 40 more hydrophilic. This results inliquid penetrating the topsheet 40 faster than it would if the surfacewere not treated. This diminishes the likelihood that menstrual fluidswill flow off topsheet 40 rather than being absorbed by the absorbentcore 44. Preferably, any portions of the topsheet 40 that overlay theflaps 24 are not treated with the surfactant. This will minimize anytendencies fluids may have to spread laterally across the flaps and tocome in contact with the wearer's thighs and other parts of the wearer'sbody.

In preferred embodiments, the inner surface 40b of topsheet 40 issecured in contacting relation with the absorbent core 44. Thiscontacting relationship results in liquid penetrating topsheet 40 fasterthan if the topsheet 40 were not in contact with absorbent core 44. Thetopsheet 40 can be maintained in contact with absorbent core 44 byapplying adhesive to the inner surface 40b of the topsheet 40. Suitableadhesives useful for this purpose are described in U.S. Pat. No.4,917,697. The adhesives can be applied by the same methods as thesurfactant is applied to the outer surface 40a of the topsheet 40.

The absorbent core 44 is positioned between the topsheet 40 and thebacksheet 42. The absorbent core 44 provides the means for absorbingmenstrual fluid. The absorbent core 44 need not have an absorbentcapacity much greater than the total amount of menstrual fluidanticipated to be absorbed. The absorbent core 44 is generallycompressible, conformable, and non-irritating to the user's skin. It cancomprise any material used in the art for such purpose. Examples includecomminuted wood pulp which is generally referred to as airfelt, crepedcellulose wadding, absorbent foams, absorbent sponges, synthetic staplefibers, polymeric fibers, hydrogel-forming polymer gelling agents, peatmoss, or any equivalent material or combinations of materials.

Polymeric gelling agents are those materials which, upon contact withfluids (i.e., liquids) such as water or body fluids, imbibe such fluidsand thereby form hydrogels. In this manner, fluids discharged into theabsorbent core 44 can be acquired and held by the polymeric gellingagent, thereby providing the articles herein with enhanced absorbentcapacity and/or improved fluid retention performance.

The polymeric gelling agent which is employed in the absorbent core 44will generally comprise particles of a substantially water-insoluble,slightly cross-linked, partially neutralized, hydrogel-forming polymermaterial. The term "particles", as used herein, can refer to particlesin any form, such as in the form of pellets, flakes, or fibers. Thecharacteristics of the absorbent core 44 (including, but not limited tothe preferred types of polymer materials used therein, and types ofmethods which can be used for preparing these polymer particles) aredescribed in greater detail in U.S. Pat. No. 5,009,653 issued to Osbornand the patents incorporated by reference in that patent, thedisclosures of which are all incorporated by reference herein.

In one preferred embodiment, the absorbent core 44 is a laminatecomprised of a layer of superabsorbent polymer material, such as in theform of particles, disposed between two air-laid tissues, first andsecond tissue layers (or "upper" and "lower" tissue layers). The firstand second tissue layers provide containment of the superabsorbentpolymer material, improve lateral wicking of the absorbed exudatesthroughout the absorbent core 44 and provide a degree of absorbency.

A suitable laminate is the superabsorbent laminate WATER-LOCK L-535available from the Grain Processing Corporation of Muscatine, Iowa(WATER-LOCK registered TM by Grain Processing Corporation). Suchsuperabsorbent laminates are disclosed in U.S. Pat. No. 4,467,012,entitled "Composition For Absorbent Film And Method Of Preparation",which issued to Pedersen et al. on Aug. 21, 1984, and U.S. Pat. No.4,260,443, entitled "Laminated Absorbent Process", which issued toLindsay et al. on Apr. 7, 1981.

In a particularly preferred embodiment, the absorbent core 44 is alaminate as described above which is slitted or partially slitted forlongitudinal extensibility as shown in FIG. 14 in the accompanyingdrawing figures. This slitted or partially slitted core is described ingreater detail in the Capillary Channel Fiber patent applications.

The backsheet 42 is impervious to liquids and, thus, prevents menstrualfluid from soiling the clothing of the user. Any material used in theart for such purpose can be utilized herein. Suitable materials includeembossed or nonembossed polyethylene films and laminated tissue. Asuitable polyethylene film is manufactured by Monsanto ChemicalCorporation and marketed in the trade as Film No. 8020.

In one alternative embodiment of the sanitary napkin 20 (typically inwhich the topsheet 40 overlays only the main body portion 22 and doesnot extend out to form the top surface of the flaps), the backsheet 42may be comprised of two layers. In such a case, the backsheet 42 maycomprise a first layer of lofted material disposed on the core-facingside 42a of the backsheet. The purpose of the first layer is to providea comfortable, non-irritating surface against the body of the wearer.The lofted layer may be comprised of any suitable material, such as anonwoven material. Preferably, the lofted layer comprises a hydrophobicnonwoven material. The second layer may be disposed on the garment side42b of the backsheet 42, and may comprise a fluid impervious film. A lowdensity polyethylene material about 0.01 to about 0.05 millimeters inthickness, preferably about 0.02 millimeters in thickness, has beenfound to work well as this second layer. A polyethylene film, such as issold by the Ethyl Corporation, Visqueen Division, under model XP-39385has been found particularly well suited for this second layer. Thebacksheet 42 may also be made of a soft, cloth-like material which ishydrophobic relative to the topsheet 40. A polyester or polyolefinicfiber backsheet 42 has been found to work well. A particularly preferredsoft, cloth-like backsheet 42 material is a laminate of a polyesternonwoven material and a film such as described in U.S. Pat. No.4,476,180 issued to Wnuk on Oct. 9, 1984.

A particularly preferred extensible backsheet 42 is an extended adhesivefilm Formula #198-338 manufactured by the Findley Adhesives Company ofWauwatosa, Wis. which is described in greater detail in the CapillaryChannel Fiber patent applications.

As shown in FIGS. 1 and 1A, the topsheet 40 is secured to backsheet 42along a first seam, such as seam 36. The seam 36 can be formed by anymeans commonly used in the art for this purpose such as by gluing,crimping, or heat-sealing. The seam 36 is illustrated in Figure 1 asextending completely around the periphery of the main body portion 22.This is a preferred embodiment for ease of construction. (Other means ofuniting the various elements can be used.)

The main body portion 22 is the portion of the sanitary napkin 20 thatcontains an absorbent means, such as absorbent core 44. The main bodyportion 22 has a liquid pervious body contacting surface (represented inFIG. 1A by topsheet 40) and an opposed liquid impervious surface(represented in FIG. 1A by backsheet 42). It is to be understood thatthe embodiment illustrated is only one possible embodiment, albeit apreferred one. Other possible embodiments include one in which anabsorbent core 44 is essentially completely wrapped with topsheet beforeit is placed on a backsheet. The main body portion 22 can also comprisean absorbent core which possesses sufficient integrity to stand aloneand is liquid pervious on one surface while the other surface has beentreated to render it liquid impervious.

The main body portion 22 may be relatively thick or relatively narrowand thin. A narrow main body portion 22 may be effective because theoverall configuration and use of sanitary napkin 20 results in main bodyportion 22 being maintained in close proximity to the body. Suchproximity of main body portion 22 places it precisely where it shouldbe: very near the body at the vaginal opening. The main body portion 22can then absorb the vast majority of the menstrual fluid (menses) beforeit has an opportunity to flow along the sides of the main body portion22. A thin main body portion may also be desired because it is typicallycomfortable to the user.

FIGS. 1 and 1A also show the fasteners, such as adhesive attachmentmeans, central pad adhesive 54 and flap adhesive 56, which are adaptedto secure the sanitary napkin 20 to the crotch region of anundergarment.

The central pad adhesive 54 provides an adhesive attachment means forsecuring main body portion 22 in the crotch portion of a panty. Theouter surface of flap 24, adjacent the distal edge 34 of the flap, ispreferably coated with a flap adhesive 56. The flap adhesive 56 is usedto assist in maintaining the flap 24 in position after it is wrappedaround the edge of the crotch portion of the panty as described below.The flaps 24 can be maintained in position by attaching the flaps 24 tothe undergarment, or to the opposing flap. Suitable adhesive fastenersare described in greater detail in U.S. Pat. No. 4,917,697.

The fasteners used with the present invention are not limited toadhesive attachment means. Any type of fastener used in the art can beused for such purpose. For example, the sanitary napkin 20 could besecured to the wearer's undergarment by the fastener described in U.S.Pat. No. 4,946,527 entitled "Pressure-Sensitive Adhesive Fastener andMethod of Making the Same" issued to Battrell on Aug. 7, 1990. Forsimplicity, however, the fasteners will be described in terms ofadhesive attachment means.

The adhesive attachment means are respectively covered by removablerelease liners, central pad release liner and flap release liner, bothdesignated 58. The pressure-sensitive adhesives should be covered withrelease liners 58 to keep the adhesives from sticking to extraneoussurfaces prior to use. Suitable release liners are described in U.S.Pat. No. 4,917,697.

While a preferred sanitary napkin embodiment of the present inventionhas been described, numerous other sanitary napkin embodiments havingflaps are available and are disclosed in the literature. These could beprovided with the zones of differential extensibility of the presentinvention. In particular, sanitary napkins having flaps are disclosed inU.S. patent application Ser. No. 07/707,233 entitled "Sanitary NapkinHaving Laterally Extensible Means for Attachment to the Undergarment ofthe Wearer", filed May 21, 1991 in the name of Osborn, et al., U.S. Pat.No. 5,009,653 and 4,950,264, both entitled "Thin, Flexible SanitaryNapkin" which issued to Osborn on Apr. 23, 1991 and Aug. 21, 1990,respectively, U.S. Pat. No. 4,917,697 entitled "Sanitary Napkin HavingFlaps and Stress Relief Means" which issued to Osborn, III, et al. onApr. 17, 1990, U.S. Pat. No. 4,687,478, entitled "Shaped Sanitary NapkinWith Flaps", which issued to Van Tilburg on Aug. 18, 1987, U.S. Pat. No.4,589,876, entitled "Sanitary Napkin", which issued to Van Tilburg onMay 20, 1986, U.S. Pat. No. 4,285,343, entitled "Sanitary Napkin" whichissued to McNair on Aug. 25, 1981, U.S. Pat. No. 3,397,697, entitled"Disposable Sanitary Shield For Undergarments", which issued to Rickardon Aug. 20, 1968, and U.S. Pat. No. 2,787,241, entitled "SanitaryNapkin", which issued to Clark on Apr. 2, 1957.

Suitable absorbent articles in the form of pantiliners are disclosed inU.S. Pat. No. 4,738,676 entitled "Pantiliner" issued to Osborn on Apr.19, 1988. Suitable absorbent articles, at least some of which are in theform of adult incontinence products, are described in U.S. patentapplication Ser. No. 07/637,571 entitled "Absorbent Article Having RapidAcquiring Wrapped Multiple Layer Absorbent Body" filed by Barry R.Feist, et al. on Jan. 3, 1991.

The disclosures of all patents, patent applications (and any patentswhich issue thereon, as well as any corresponding published foreignpatent applications), and publications mentioned throughout thisdescription are hereby incorporated by reference herein. It is expresslynot admitted, however, that any of the documents incorporated byreference herein teach or disclose the present invention.

The characteristics of the flaps 24 will now be looked at in greaterdetail. The general construction of flaps 24 suitable for use in thepresent invention (without the zones of differential extensibility isdescribed in greater detail in the patents incorporated by referenceherein.

The overall size of the flaps 24 can be readily selected by thoseskilled in the art. Preferably, the flaps 24 are sized so that thesanitary napkin 20 is from about 10 to about 23 centimeters wide betweenthe distal edges 34 of the flaps at their greatest separation.Preferably each flap 24 is from about 5 to at least about 19 centimeterslong in the direction parallel to the principal longitudinal centerlinel of the sanitary napkin.

The shape of the flaps 24 can be selected by those skilled in the art.Preferably, not only are the flaps 24 mirror images of each other, thetwo halves of each flap 26 and 28 are also symmetrical about the flaptransverse centerline t₁. (It should be understood that the shape andorientation of the flaps described herein are those of a preferredembodiment. They are not mandatory design features.)

In the preferred embodiment illustrated in FIG. 1, the flaps 24 arepositioned slightly forward of the principal transverse centerline t ofthe sanitary napkin. (In such a case, the flap transverse centerline t₁does not coincide with the principal transverse centerline t of thesanitary napkin 20.) The flaps 24, however, are preferably evenly spacedfrom the principal longitudinal centerline l of the sanitary napkin.

The flaps 24 can be associated with the main body portion 22 in a numberof different manners. Many of the different ways a component (such asthe flaps 24) can be "joined to" or "associated with", etc. anothercomponent which are set forth in the definitions of these termscontained in U.S. Pat. No. 5,007,906 entitled "Decoupled SanitaryNapkin" which issued to Osborn, et al. on Apr. 16, 1991. When the flapscomprise separate elements, they can be joined to the main body portion22 by any techniques known to those skilled in the art. Such techniquesinclude, but are not limited to adhesives, heat and/or pressure,ultrasonics, etc.

The flaps 24 are associated With the main body portion 22 along lines ofjuncture 30. The lines of juncture can be concave, straight, (or, butpreferably not convex) relative to the principal longitudinal centerlinel. The lines of juncture 30 may comprise those lines or areas whereseparate flap elements are joined to the main body portion 24.Alternatively, when the flaps 24 are integral with the main body portion22, the lines of juncture 30 may represent lines of demarcation betweenthe main body portion 22 and the flaps 24 (although it is not necessarythat there be a precise line of demarcation).

It is also not necessary that the flaps 24 extend from (or be joinedalong) the longitudinal edges 22a of the main body portion 22. The flaps24 can joined inward (or "inboard") from the longitudinal edges 22atoward the longitudinal centerline. The flaps 24 can, thus, each bejoined to the main body portion 22 along the principal longitudinalcenterline l, or along the longitudinal edges 22a of the main bodyportion 22, or at any place between the principal longitudinalcenterline l and the longitudinal edges 22a of the main body portion 22.The flaps 24 will, of course, generally be on opposite sides of theprincipal longitudinal centerline l.

Having now described some sanitary napkins that can be used inconjunction with the present invention (as well as the characteristicsof their flaps), the sanitary napkin of the present invention will nowbe described in greater detail with relation to the function of the samein the wearer's undergarments.

FIG. 3 is a depiction of the crotch portion 14 of an undergarment 11 ofthe type commonly worn by many women and well known as a panty. A panty11 comprises a front section 10, a back section 12, and a crotch portion14 which joins the front and back sections. The crotch portion 14comprises two side edges 16 and center crotch portion 18.

The sanitary napkin 20 of the present invention is utilized by removingthe release liners 58 and placing the sanitary napkin 20 in a panty 11as shown in FIG. 4. The center of main body portion 22 is placed incrotch portion 14 of the panty with one end of main body portion 22extending towards the front section 10 of the panty and the other endtowards the back section 12. The backsheet 42 is placed in contact withthe inner surface of center crotch portion 18 of the panty. Central padadhesive 54 maintains main body portion 22 in position. The distalportions of flaps 24 are folded around the side edges 16 of the panty.The flap adhesives secure the flaps 24 to the underside of the panty.

When the flaps 24 are folded down around the edge 16 of the crotchportion 14 of the panty, stresses are developed in the flaps,particularly in the corner regions 52' of the same. These stresses aremagnified when the flaps 24 are folded under the panty and attached tothe panty's underside. The stresses are further magnified when the pantyis pulled up into position and the elastics in the panty edges 16 forcethe folded portion of the flaps into the uppermost part of the wearer'scrotch and thigh.

The stresses are most highly concentrated along the fold 19 where theflap 24 changes from being disposed on the bodyside of the panty tobeing located on the underside of the panty. In other words, thestresses are concentrated at the edge 16 of the crotch portion 14 of thepanty 11. The stresses in the flaps 24 generally follow the arc formedby the edges 16 of the crotch portion 14. These stresses may cause thecorner regions 52' of the flaps 24 to bunch longitudinally inward. Thisreduces the area of the wearer's undergarments the flaps are able tocover. If the stresses are great enough, the flaps 24 can becomedetached from the panty and the flaps 24 will be less than optimallyeffective. Depending on the design of the sanitary napkin, the arc ofconcentrated stresses may or may not coincide with the lines of juncture30 between the flaps 24 and the main body portion 22.

In order to eliminate, or at least reduce these stresses, the sanitarynapkin 20 is provided with zones of differential extensibility 50. Thezones of differential extensibility 50 preferably reduce the stressesalong the fold 19 to such a degree that the flaps 24 will remainattached to the underside of the panty and will not lose their abilityto cover a given area of the wearer's undergarments.

Referring again to FIG. 1, one preferred type of zone of differentialextensibility 50 which was described briefly above, comprises the slackin the corner regions 52' of the flaps. The characteristics of the zonesof differential extensibility 50 are described in greater detail below.That is followed by a discussion of some alternatively preferred typesof zones of differential extensibility.

The zones of differential extensibility 50 are, as noted above, mostpreferably located at those points where the edges 35 of the flaps 24intersect the edges 16 of the panty when the sanitary napkin 20 is worn.

The points of intersection can generally be determined by having aperson wear a particularly designed napkin having flaps and a fairlycommonly designed panty. Commonly, panties have a crotch width of about5.0 to about 9.O centimeters. Marks can then be made on the bottomsurface of the sanitary napkin 20 where the sanitary napkin 20intersects the panty. The points of intersection between the flap 24 andthe edge 16 of the panty generally coincide with the ends of the fold19. Assuming the napkin has two flaps, the four marks will mark thegeneral locations for the zones of differential extensibility 50. Thezones of differential extensibility 50 may be located along the lines ofjuncture 30, outboard of the lines of juncture in the flaps 24, orinboard of the lines of juncture. Commonly, the zones of differentialextensibility 50 will begin at a point located between the area of theflap transverse centerline t₁ and about 1.5 centimeters in thelongitudinal direction from the flap transverse centerline t₁.

The zones of differential extensibility 50 may be of any shape.Typically, they will form a three-sided figure (roughly triangular,pie-shaped, or fan-shaped) in plan view when they are fully extended.Often, the figure defined by the zones of differential extensibilitywill have two sides that are of approximately equal length and a shorterside. The edge 35 of the flaps 24 usually forms the shorter side. Itshould be understood, however, that the precise shape of the zones ofdifferential extensibility 50 is not always as critical as the locationand extensibility properties of the same. Likewise, it is not criticalfor there to be precise line of demarcation that marks the boundaries ofthe zones of differential extensibility 50 (or the boundaries of thecomplementary first portions of the quarters of the sanitary napkin).Thus, there can be a gradual transition between the zones ofdifferential extensibility 50 and the first portions of the quarters ofthe sanitary napkin.

The zones of differential extensibility 50 may be bounded on one side bythe line of juncture 30. Alternatively, the boundary may be adjacent theline of juncture 30. If the zones of differential extensibility 50 areprovided in the main body portion 22 (for instance, if they are formedby a fold made through the main body portion 22 (as described below)),however, this boundary may be as far inboard as the principallongitudinal centerline l. The zones of differential extensibility 50are typically bounded at the ends by at least a portion of the edge 35of the flap 24. This is often a curved line. (The zones of differentialextensibility 50 can also be bounded at the ends by a portion of thelongitudinal edges 22a of the main body portion and/or transverse or endedges 22b of the main body portion 22.) The third side of the zones ofdifferential extensibility is typically formed by a boundary 51 whichmay be an imaginary line that runs from the point of the zone ofdifferential extensibility 50 which is either located on the flaptransverse centerline t₁ (or nearest to the same), to a point on theedge 35 of the flap 24.

The total area covered by the zones of differential extensibility 50 canvary widely. The area can cover a relatively large portion of thesanitary napkin, provided there remain some portions of the sanitarynapkin adjacent at least portions of the principal longitudinalcenterline and the flap transverse centerline that are less extensible.The zones of differential extensibility 50 can be provided along theentire juncture 30 of the flaps 24 with the main body portion 22. Inalternative embodiments, the zones of differential extensibility 50 canbe provided throughout the entire flap (for instance, if the entire flapis pleated with longitudinally-oriented pleats). Preferably, however, inthe present invention, zones of differential extensibility 50 are notprovided either along the entire juncture 30 or throughout the entireflap. There are several reasons for this.

First, due to the curvature of the panty crotch, all portions of theflaps are not stressed the same amount when the flaps are wrapped arounda panty crotch. Typically, the portion of the flaps located adjacent theflap transverse centerline t₁ (the center portion 27 of the flap) willnot be subjected to stresses that are as great as those exerted on theflap corner regions 52'. Thus, it is possible that the center portion 27of the flaps (and possibly also the adjacent regions of the main bodyportion 22) could be constructed so that it is not provided with anyextensibility properties. Alternatively, the center portion 27 (andadjacent regions) could merely be less extensible than the cornerregions 52 of the sanitary napkin.

Second, it is preferable that the corner regions 52' of the flaps 24stretch a greater distance in the transverse direction than the centerportion 27 of the flaps for the best fit and for the flaps 24 to adaptproperly to the curvature of the crotch of the wearer's undergarments.This allows the boundary 51 defined by the zones of differentialextensibility to correspond to the configuration of the edges of thecrotch of the wearer's panties.

Third, depending on the process used to create the zones of differentialextensibility 50, it may be less expensive to provide differentialextensibility in only certain portions of the sanitary napkins.

The amount of differential extensibility needed can vary depending on anumber of factors. These include, but are not limited to the size andconfiguration of the wearer's panties, the size and configuration of theflaps, etc. Any amount of differential extensibility in the cornerregions 52 will provide some benefit versus a sanitary napkin that isnot provided with zones of differential extensibility. The amount ofdifferential extensibility should not be so great, however, that theexcess material that comprises the zones of differential extensibility50 causes the sanitary napkin to fit sloppily adjacent the wearer'spanties and her body.

Preferably, the amount of differential extensibility is sufficient tosubstantially reduce the stresses on the flaps when the sanitary napkinis worn. Typically, a conservatively configured zone of differentialextensibility 50 is one which when fully extended, defines a linearboundary 51 (i.e., one which forms a straight line) that runs from theintersection of the flap transverse centerline t₁ and the line ofjuncture 30 to the point on the edge 35 of the flap 24 where the flap 24intersects the edge 16 of the panty crotch. A zone of differentialextensibility 50 with a linear configuration is said to beconservatively configured because it will ordinarily provide asufficient amount of extensibility in most cases to relieve the stressesin the flaps 24. In an ideal case, the boundary 51 will correspond tothe configuration of the edges 16 of the crotch of the wearer's panties.

FIGS. 2 and 2A show a sanitary napkin having another type of zone ofdifferential extensibility. The sanitary napkin 20 shown in FIGS. 2 and2A has flaps with corner regions 52 that have been provided withdifferential extensibility by ring rolling these corner regions inaccordance with the above-described ring rolling patents and patentapplications. The ring rolling (or pre-corrugating) should be applied sothat the fold lines 60 in the corrugations are oriented generally in thelongitudinal direction. The phrase "generally in the longitudinaldirection" (and similar phrases), as used herein, means oriented more inthe longitudinal direction than in the transverse direction. Thus, thefold lines 60 may angle away from the principal longitudinal centerlinel. This will also provide the desired transverse directionextensibility.

In variations of the embodiments of the present invention (such as theembodiment shown in FIG. 2 and 2A), the amount of extensibility providedcan be varied throughout different portions of the zones of differentialextensibility 50. For instance, the number or amplitude of thecorrugations formed by the ring rolling could be varied so that eitheror both these characteristics are greater further from the flaptransverse centerline t₁. This will allow the sanitary napkin to beprovided with differential extensibility characteristics that mostclosely match the configuration of a panty crotch.

FIGS. 5 and 6 show another alternative embodiment of the sanitary napkinof the present invention. The sanitary napkin 20 shown in FIGS. 5 and 6has been provided with zones of differential extensibility 50 bypleating and then gathering in portions of the flaps.

The flaps 24 are pleated or folded with generallylongitudinally-oriented fold lines 62. The fold lines 62 can run alongand/or outboard (or even inboard) of the juncture 30 of the flaps andthe main body portion 22. The pleats preferably run the length of thejuncture 30. The pleated sections of the flaps (the "pleats") 64 arepreferably folded on top of each other (that is, stacked perpendicularto the plane of the sanitary napkin). In alternative embodiments, theymay be folded and arranged side-by-side. The pleated sections aregathered in or restrained from opening by a flap pleat restraint 66located along the flap transverse centerline t₁. This provides thesanitary napkin, and particularly the flaps 24, with corner regionswhich are extensible in the transverse direction and with centerportions 27 (along the flap transverse centerline t₁) which are not.

In such a pleated embodiment, the flaps 24 can be provided with anynumber of fold lines. For instance, in the most basic form of thepleated embodiment, the flaps can simply be folded inward toward theprincipal longitudinal centerline l along a single line along thejuncture 30 and tacked to the main body portion 22 at a point inboard ofthe juncture 30 (which is preferably in the area of the flap transversecenterline t₁). Typically, however, as shown in FIG. 6, the flaps willhave at least two pleat fold lines 62.

The flap pleat restraint 66 can be any suitable type of element capableof keeping a portion of the pleated material from unfolding. The flappleat restraint 66 can be located along the flap transverse centerlinet₁, or it can be spaced some distance away from the flap transversecenterline t₁. The flap pleat restraint 66 is, however, preferablylocated at some place along the flap transverse centerline t₁. Thiscreates flaps with pleats which are able to open up an equal amount inboth the front and back halves 26 and 28 for a preferred fit around thepanty crotch. The flaps 24 can have two flap pleat restraints 16, onelocated along (or spaced some distance away from) the flap transversecenterline t₁ for each flap, or they can have a single flap pleatrestraint that spans from one flap to the other.

The flap pleat restraint 66 shown in FIG. 6 is an "interior" restraint,i.e., it is located in between two pleated or folded sections 64 of theflaps 24. In alternative embodiments, the flap pleat restraint 66 can beof a type which secures the pleated sections 64 of the flaps 24 fromoutside (or exterior) of the pleated sections.

The flap pleat restraint 66 may be of any size provided it is no largerthan the length of the juncture 30. This allows the pleated sections 64of the flaps 24 to open properly. This is the case since the pleatedsections 64 of the flaps 24 will typically open from the ends 30a and30b of the lines of juncture to the flap pleat restraint 66. It may,therefore, be preferable for the flap pleat restraint 66 to be as smallas possible to minimize interference with the opening of the pleatedsections 64. The flap pleat restraint 66 should also be located at apoint on the pleated section 64 that is relatively close to theprincipal longitudinal centerline l. This will ensure that the pleatwill not unfold and lose its effectiveness.

The flap pleat restraint 66 can be of any suitable construction.Suitable flap pleat restraints 66 include, but are not limited toadhesives, ultrasonic bonds, heat and/or pressure bonds, tapes, etc.These different types of flap pleat restraints can be in an unlimitednumber of configurations. Such configurations can include spots, lines,patches, etc.

The dimensions of some suitable pleats for embodiments such as thoseshown in FIGS. 5 and 6 are set forth in the following Table 1.

                  TABLE 1                                                         ______________________________________                                        PLEAT SIZES                                                                   Length of Flap                                                                             Width of Pleat                                                                            Effective Pleat                                      (in.)        (in.)       Size (in.)                                           ______________________________________                                        3            0.43        0.14                                                 3.5          0.50        0.19                                                 4            0.58        0.26                                                 4.5          0.65        0.33                                                 5            0.73        0.40                                                 5.5          0.81        0.50                                                 6            0.90        0.60                                                 6.5          1.00        0.72                                                 7            1.11        0.86                                                 7.5          1.23        1.03                                                 8            1.40        1.24                                                 ______________________________________                                    

The dimensions in Table 1 are non-limiting examples of the sizes ofpleats which may be useful in providing a sanitary napkin with suitablezones of differential extensibility 50. The dimensions are based on asanitary napkin embodiment which has a pleat 9 inches long. The lengthof the pleat (designated P_(l) in FIG. 15) is measured from one end ofthe line of juncture to the other (from 30a to 30b) in a directionparallel to the principal longitudinal centerline l.

The length of the flaps 24 referred to in Table 1 is measured along thepleat line 62 that is closest to the distal edge 34 of the flap 24 whenthe pleat restraint 66 is removed and the flap is unfolded. The distancebetween these two points 62a and 62b is designated F_(l) in FIG. 15. Thewidth of the pleat, P_(w), is the distance between fold lines 62. The"effective pleat size" refers to a number calculated by multiplying thewidth of the pleat times the ratio defined by the length of the flapover the length of the pleat.

The effective pleat size serves as an approximation of the amount thepleat will open in the corner regions 52 of the sanitary napkin. FIG. 15shows this schematically. The line designated 0 in FIG. 15 representsthe approximate location of edges of the pleated sections when the pleatis in a fully opened or extended configuration. FIG. 15 shows that inthis embodiment the points on the pleated sections spaced longitudinallyfarthest from the flap transverse centerline t₁ will generally fan openfully (toward point 0₁) while the points such as 62a in the cornerregions 52 of the sanitary napkin will only open partially (to point0₂). The effective pleat size recognizes that the lesser amount whichthe pleated sections will open in the corner regions is directlyproportional to the relationship between the length of the flaps and thelength of the pleat (i.e., perhaps better understood and morespecifically as being proportional to the ratio defined by 1/2 F_(l)over 1/2 P_(l)).

The width of the pleat and the number of folds in the pleats determinesthe amount of extensibility of the pleated material. The amount ofextensibility (or slack material) in the corner regions 52 can, thus, becalculated by multiplying the number of folded sections of the pleatedsection times the effective pleat size. Thus, in embodiments shown inFIG. 15 having two folded sections 64a and 64b, the amount of slack ineach corner region 52 is approximately equal to twice the effectivepleat size.

In addition to being useful for determining the amount of extensibilityin the corner regions of pleated sanitary napkin embodiments, theeffective pleat size and other measurements provided herein can even beused more broadly. The effective pleat size figures provided can be usedas guidelines for determining the amount of extensibility for theembodiments described herein having different types of zones ofdifferential extensibility. The relationship between the dimensions ofthe pleats provided above and the dimensions of interest in the otherembodiments described herein can be arrived at by one skilled in theart. (For example, FIG. 15 shows an example of the use of pleat widths.The curved dotted line shown in FIG. 15 represents a suitable locationfor the curved juncture in the embodiment (described below) in whichzones of differential extensibility 50 are provided by attaching theflaps 24 along a curved juncture. The curved juncture curves inward inan amount equal to the width of the pleat.)

FIG. 7 shows an alternative embodiment of a sanitary napkin havingpleated flaps in which the flaps 24 are pleated, folded over, andsecured to the garment side 20b of the sanitary napkin 20 rather thanthe body-facing side 20a (as in the embodiment shown in FIG. 6).

FIG. 8 shows another alternative embodiment of the sanitary napkin 20 ofthe present invention in which the flaps 24 are attached along lines ofjuncture that are curved concave inward toward the principallongitudinal centerline l. When the flaps 24 in such an embodiment arefolded outward, excess flap material is present in the corner regions52.

In this embodiment, the sanitary napkin 20 may have two longitudinaljunctures, such as 30 and 30', adjacent each longitudinal edge of themain body portion.

The sanitary napkin 20 can have a first longitudinal jucture (or an"outboard" longitudinal juncture) 30 where the flap 24 is attached to orextends from the main body portion 22. A second longitudinal juncturecan be present (or "inboard" longitudinal juncture) 30' that is used toprovide the sanitary napkin 20 with the desired zones of differentialextensibility 50.

The first longitudinal juncture 30 is shown as being a curved line inFIG. 8. However, it need not be curved. It can be in any form describedabove as being suitable for the lines of juncture. The secondlongitudinal juncture 30', however, will generally always be curvedconcave inward toward the principal longitudinal centerline l.

The sanitary napkin 20 shown in FIG. 8 can be made from any sanitarynapkin that is provided with flaps. A securement means, such as a lineof adhesive 68 is laid down on either the body-facing side 20a or thegarment side 20b of the sanitary napkin in the pattern desired for thesecond longitudinal juncture (or "curved juncture") 30'. The flaps 24are then folded over onto the aforementioned side of the sanitary napkinand sealed by the securement means. The securement means can compriseany means known in the art for securing such materials togetherincluding, but not limited to heat and/or pressure sealing, ultrasonics,and, of course, adhesives.

In a preferred embodiment, the excess flap material between the firstand second longitudinal junctures 30 and 30' can be trimmed to providethe sanitary napkin 20 with curved longitudinal side edges. Theformation of the zones of differential extensibility in this mannerallows location and curvature of the curved juncture 30' to becontrolled. In a preferred emodiment, the curvature of the curvedjuncture 30' can be established to coincide with the curvature of thepanty crotch.

FIG. 8A shows an example of a sanitary napkin that employs another wayof attaching the flaps 24 along a curved line of juncture 30.

In the embodiment shown in FIG. 8A, the flaps 24 are only attached alonga single curved juncture 30. As shown in FIG. 8A, the longitudinal sideedges 22a of the main body portion 22 are curved concave inward towardthe principal longitudinal centerline l. The flaps 24 are attached alongthe single juncture 30 that runs along the curvature of the longitudinalside edges 22a of the main body portion 22.

FIG. 8A also shows that the curved juncture 30 only needs to be curvedconcave inward in the central region 104 of the sanitary napkin. (Thesame is true for virtually all of the curved juncture embodimentsdescribed herein.) The curved juncture 30 can be in any suitableconfiguration in the end regions of the sanitary napkin. For instance,the juncture 30 can be straight, or (as shown in FIG. 8A) curved convexoutward in the end regions 100 and 102. The central region 104 isdisposed between the first end region 100 and the second end region 102.The end regions extend longitudinally outward from the central region104 about 1/8 to about 1/3 of the length of the sanitary napkin. (Theterms "central region" and "end regions" are defined in greater detailin U.S. Pat. No. 4,690,680 issued to Higgins on Sep. 1, 1987.)

In fact, the juncture 30 need not be curved at all to provide some ofthe desired benefits obtained when using a curved juncture. The juncture30 only needs to have some points, such as 106, in the central region104 of the sanitary napkin that are more inwardly diposed than thepoints, such as 108, that lie along the juncture 30 in the end regions102 and 104 of the sanitary napkin. Thus, the juncture 30 could beformed by two or more straight lines or segments (and/or curvedsegments). The lines will typically be angled inwardly toward theprincipal longitudinal centerline l as they approach the central region104 of the sanitary napkin. Curved junctures are preferred, however,because they correspond most closely to the shape of the edges of thepanty crotch.

The proximal edges 32 of the flaps 24 shown in FIG. 8A are either on, orslightly laterally outboard of the securement means 68. The proximaledges 32 of the flaps 24 can be of various different configurations aslong as this relationship is maintained. Preferably, the curvature ofthe proximal edges 32 of the flaps 24 closely matches the curvature ofthe longitudinal side edges 22a of the main body portion 22.

The flaps 24 can be attached to either side (20a or 20b) of the sanitarynapkin 20 (as in the case of many of the embodiments described herein).Preferably, however, the flaps 24 are attached to the body-facing side20a of the sanitary napkin. This has the advantage that the sanitarynapkin can be placed in the wearer's undergarments with the flaps 24 inthe folded inward configuration shown in FIG. 8A. The user does not haveto unfold, or otherwise manipulate the flaps 24 before attaching themain body portion 22 to the panty crotch. The flaps 24 are then foldedback outward around the edges of the panty crotch and attached to theunderside of the panty. Preferably, in cases such as this, where theflaps are initially oriented inwardly, they are comprised of a materialsufficiently flexible that the flaps will not tend to fold back inwardwhen they need to be folded back for attachment to the underside of thewearers panties.

FIG. 8A also provides an example of flaps 24 that can be manufacturedwith a minimum of wasted material. This is particularly important incases where the flaps are made of a relatively expensive material.

The flaps 24 for the embodiment shown in FIG. 8A are preferably cutprior to the attachment of the same to the main body portion 22. Asshown in FIG. 8B, the flaps 24 are preferably both cut from the same webof material 110. The web of material 110 need only be as wide as thelateral width of one flap (or only slightly wider than the width of aflap). The edges of the web of material oriented in the machinedirection can be trimmed to the desired curvature for the proximal edgesof the flaps. After the edges are trimmed, the edges 35 of the flaps canbe formed by cutting the web along a sinusoidal path.

The sinusoidal cutting path can have an amplitude that extends from oneedge of the web to the other. The sinusoidal cutting path forms flappieces which are "nested" with each other. The cutting path can, thus,simultaneously form the edges of two different flaps. For instance, theweb of flap material can be cut so that the material forming the portionof the edges designated 35' and 35" is abutting and the sinusoidalcutting path forms both flap edges.

FIGS. 8C-8E show an example of a sanitary napkin that employs stillanother way of attaching the flaps 24 along curved lines of juncture 30to create slack in the corner regions 52. The attachment is accomplishedin the following manner.

In the embodiment shown in FIGS. 8C-8E, the sanitary napkin 20 flaps 24that comprise separate pieces attached to the backsheet 42 (these piecescould, of course, be attached to another component of the sanitarynapkin 20). The longitudinal side edges 22a of the main body portion 22of the sanitary napkin 20, prior to the attachment of the flaps 24, arerelatively straight.

A piece of material, extension 70, is provided which is attached alongeach longitudinal edge 22a of the main body portion 22. The extension 70extends the longitudinal side edges 22a of the main body portion 22 ofthe sanitary napkin 20 outward from the direction of the principallongitudinal centerline l. The extension 70 can be any suitablematerial. Preferably, the extension comprises backsheet material. In onepreferred embodiment, the extension 70 comprises a nonwoven/fluidimpervious film laminate similar to that described above as beingsuitable for use as the backsheet.

The extension 70 has two longitudinal edges 70a and two transverse edges70b. The longitudinal edges 70a comprise a proximal longitudinal edge(or simply "proximal edge") 70a' and a distal longitudinal edge (orsimply "distal edge") 70a". In the embodiment shown, the proximal edge70a' of the extension 70 is preferably a relatively straight line andthe distal edge 70a" is curved concave inward toward the principallongitudinal centerline l of the sanitary napkin. The radius ofcurvature of the distal edge 70a" is designated in FIG. 8E as the firstradius of curvature, r₁.

The transverse edges 70b of the extension 70 can be of any suitableconfiguration. Preferably, the transverse edges 70b are of a curvedconvex outward configuration, similar to that shown in the drawings, sothat they will present a comfortable shape for the wearer.

The flaps 24 are provided in the form of separate crescent-shaped piecesof material 72. The crescent-shaped pieces 72 each have two curvededges, 72a and 72b. One of the edges, 72a, has a smaller radius ofcurvature (second radius of curvature r₂) than the other edge 72b (whichhas a third radius of curvature r₃). The edges 72a with the smallerradius of curvature r₂ (i.e., the edge with more curvature) form thedistal edge 34 of the flaps 24. The edges 72b with the larger radius ofcurvature r₃ form the proximal edges 32 of the flaps.

The radii of curvature are established so the third radius of curvaturer₃, is less than the radius of curvature r₁ (the radius of curvature ofthe distal edge 70a" of the extension piece 70.)

There is a zone along the edge 72b with the larger radius of curvaturethat has a plurality of spaced apart notches 76 cut into it (shown inFIG. 8D). The zone comprises the flange 74 of the flaps 24. The flange74 can be of any suitable dimensions which allows the flaps 24 to beattached to the extension 70. In the embodiment shown, the flange isabout 1/4 inch (about 6 mm.) in width. The notches 76 are preferablyabout 0.2 inch (about 5 mm.) in depth and about 0.15 inch (about 4 mm.)in width at their widest point. The notches 76 allow the flange 74 tospread out sufficiently so that the first and third radii of curvature,r₁ and r₃, become approximately the same. This allows the flaps 24 to beattached along the flange 74 to the edge of the extension piece 70without puckering, etc.

The flange 74 can be attached to the extension 70 by any suitablesecuring element, or attachment means. For instance, as shown in FIG.80, the securing element used to attach the flaps 24 to the extension 70can include, but is not limited to a plurality of spaced apart pieces ofdouble-sided tape 80 that are placed along those areas of the flange 74,designated 78, that lie between the notches 76. (The double-sided tapepieces are placed along the unnotched portions of the flange.)

In an alternative embodiment, which is somewhat preferred over theembodiment described above, the extension 70 can be made integral withthe main body portion 22. That is, rather than attaching a separateextension piece to each longitudinal side edge of the sanitary napkin20, the longitudinal side edges of the main body portion 22 (or acomponent thereof, such as backsheet 42) could merely be extendedfurther outboard away from the principal longitudinal centerline l. Thelongitudinal side edges 22a of the main body portion 22 could then becut to form a curved edge similar to that of the distal edge 70a" of theextension 70 described above.

FIGS. 9-11 show still another alternative embodiment of the sanitarynapkin 20 of the present invention. In this embodiment, the entiresanitary napkin 20 is folded or pleated through the main body portion 22of the sanitary napkin. The sanitary napkin 20 is folded or pleatedalong two longitudinal lines 90, one of which is located on each side ofthe principal longitudinal centerline l. The pleated section of the mainbody portion 22 is restrained from opening along the flap transversecenterline t₁.

This also creates zones of differential extensibility 50 (or slack) inthe corner regions 52 of the sanitary napkin 20. The zones ofdifferential extensibility 50 are formed in the flaps 24, as well as inportions of the main body portion 22, particularly those portions whichlie between the corner regions of the flaps 52' and the principallongitudinal centerline l. The zones of differential extensibility 50are formed because the portions of the components of the sanitary napkin20 are all gathered in along the flap transverse centerline t₁ (shownbest in FIG. 10) while the portions of the components of the sanitarynapkin spaced longitudinally away from the flap transverse centerline t₁are gathered in to a lesser extent the farther they are spacedlongitudinally away from the flap transverse centerline t₁. (Note thatthe cross-section of FIG. 10 is not taken through the zones ofdifferential extensibility 50).

The folding or pleating of the sanitary napkin 20 also forms a hump 92in the center of the main body portion 22. This hump 92 (although notnecessarily drawn to scale in the drawing figures) is preferably made ofsuch a size and shape that it is capable of fitting in the space betweenthe wearer's labia.

In the embodiment shown in FIGS. 9-11, the pleated section of thesanitary napkin 20 (or hump) is gathered in and restrained by a padrestraint 94. The pad restraint 94 is preferably relatively inextensibleso that it provides the desired zones of differential extensibility 50in the corner regions 52 of the sanitary napkin 20. The pad restraint 94may be in direct contact with the gathered in portions that form thehump, or it may bridge the hump. In the latter case, the pad restraint94 may extend outward as far as the proximal edges 32 of the flaps andrestrain the gathered in portions laterally outside the hump.

The pad restraint 94 can be made of any suitable material. Somenon-limiting examples of suitable materials include paper (provided thesame is not located where it can be wetted), tapes, nonwoven materials,and pieces of polyethylene film. The pad restraint 94 can also includeany type of restraint described above as being suitable for the flappleat restraint 66, and vice versa.

The sanitary napkin 20 of the present invention, as shown in FIGS. 9-11,can also have optional elastics 96 on or adjacent its flaps 24. In apreferred embodiment, the elastics 96 are located along the lines ofjuncture 30 adjacent the center portion 27 of the flaps 24. Theseelastics 96 are attached to the sanitary napkin 20 (preferably on thebacksheet 42) in an elastically contractible condition. The elastics 96assist the unrestrained pleated portions of the sanitary napkin 20 inopening so that the pleats are fully effective. The zones ofdifferential extensibility 50 created in such an embodiment are stillconsidered to be "elasticless." The elastics 96 are not used to gatherin portions of the sanitary napkin to create the zones of differentialextensibility 50, only to assist the unrestrained pleated portions inopening.

Similarly positioned elastics can be used for the same purpose in theother sanitary napkin embodiments described herein. The use of elastics96 in the embodiment shown in FIGS. 9-11, however, is particularlyimportant because it opens the unrestrained pleated portion of thenapkin 20 prior to the attachment of the sanitary napkin 20 to thewearer's undergarments with the central pad adhesive 54. (If theelastics 96 were not used, the central pad adhesive 54 may tend toremain in the form of two parallel strips rather than two concaveinwardly oriented strips as shown in FIGS. 9 and 11. If the strips ofadhesive are parallel when they are attached to the wearer'sundergarments, the effect of pleating and the gathering in therestrained portion of sanitary napkin 20 would be negated.)

FIG. 12 shows an alternative embodiment of the sanitary napkin 20 of thepresent invention in which the sanitary napkin 20 is folded or pleatedonly along one longitudinal line 90. In this case, the fold line 90should, preferably, run along the principal longitudinal centerline l.

FIG. 13 shows an alternative embodiment of the sanitary napkin 20 inwhich the sanitary napkin 20 is folded or pleated along a plurality offold lines 90. In this case, the fold lines 90 are centered about theprincipal longitudinal centerline l.

It should be apparent to one skilled in the art that in still otheralternative embodiments, the flaps 24 (rather than the main body portion22) could be provided with a single fold or multiple folds. Forinstance, the flaps 24 could be provided with folds similar to the foldsthrough the entire pad shown in FIGS. 12 and 13. It is also apparentthat in other alternative embodiments, the zones of differentialextensibility 50 of the sanitary napkin 20, rather than being integralwith the less extensible first portions of the sanitary napkin 20, couldcomprise separate pieces of material (such as separate slack material,or ring rolled, corrugated or pleated material) associated with thesanitary napkin.

FIG. 16 shows an alternative embodiment in which the sanitary napkin 20is provided with a barrier 98 along the proximal edges 32 of the flaps24. The barrier 98 stands up to serve as a wall to retain exudatesflowing in the transverse direction toward the flaps 24 (shown in theflap 24 located near the top of the sheet containing FIG. 16). Thebarrier 98 may stand up before (and after) the sanitary napkin is placedin the wearer's undergarments, or it may initially lie relatively flatagainst the topsheet and use the forces exerted by folding of the flapsdown under the wearer's undergarments to stand up. In other alternativeembodiments, the barrier 98 may have its ends tacked down near the endsof the junctures so that it slants inwardly during use rather thanstanding straight up.

The barrier 98 may be provided on most of the embodiments describedherein. (The barrier may also be provided on other sanitary napkinembodiments. For instance, the flaps of the sanitary napkin 20 shown arecompletely extensible. In addition, the sanitary napkin could even beprovided with such a barrier 98 if it did not have flaps 24.) Thebarrier 98 may be constructed in any suitable manner. FIG. 16 shows onepreferred construction in which the barrier 98 is formed by providingflaps 24 that comprise non-integral (or separate) elements. The barrier98 is formed by providing these flap elements with an extension ofexcess material inboard of the junctures 30. The barrier 98 may be madeof the same material as the remainder of the flaps 24. Alternatively, itmay (and/or the portions of the flaps adjacent the barrier) may be madeof a stiffer material to aid the barrier in standing up.

In still other alternative embodiments, the sanitary napkin could beprovided with additional components. For instance, the sanitary napkincould be provided with the wet-laid tissue and/or the liquid permeablewipe acquisition sheet described in greater detail in U.S. Pat. No.5,009,653 issued to Osborn. In addition, such sanitary napkins could beprovided with additional types of stress relief means such as thosedescribed in U.S. Pat. No. 4,917,697 at various locations around theperiphery of the sanitary napkin.

Thus, the present invention provides a sanitary napkin having flaps andzones of differential extensibility to provide an improved stress reliefmeans for relieving the stresses that develop in the flaps when theflaps are folded down and under a wearer's undergarment.

While particular embodiments of the present invention have beenillustrated and described, it would be obvious to those skilled in theart that various other changes and modifications can be made withoutdeparting from the spirit and scope of the invention.

What is claimed is:
 1. An absorbent article for wearing in a wearer'sundergarment, said absorbent article having a principal longitudinalcenterline that is oriented in a longitudinal direction, and a principaltransverse centerline that is oriented in a transverse direction, saidabsorbent article comprising:a main body portion having two spaced apartlongitudinal edges, two spaced apart transverse edges, a first endregion, a second end region, and a central region disposed between saidend regions, said main body portion comprising a liquid pervioustopsheet, a liquid impervious backsheet joined to said topsheet, and anabsorbent core positioned between said topsheet and said backsheet; apair of flaps for folding under the wearer's undergarment, one of eachof said flaps being joined to said main body portion at a juncture andextending laterally outward from each said longitudinal edge beyond anoutermost peripheral portion of said main body portion, said flapshaving a flap transverse centerline that passes through said centralregion of said main body portion, and having portions of said flaps thatare located along said flap transverse centerline, whereinsaid portionsof said flaps that are located along said flap transverse centerline lietransversely outboard of the longitudinal side edges of said main bodyportion when said flaps are extended, and said flap transversecenterline intersecting the principal longitudinal centerline of theabsorbent article and dividing the absorbent article into four quarters,each quarter comprising:a first portion of each quarter adjacent saidprincipal longitudinal centerline and said flap transverse centerline,and a second portion of each quarter outboard of said first portion ofeach quarter, said second portion of at least one of said quarterscomprising a non-elasticated zone of differential extensibility, saidzone of differential extensibility having a greater range ofextensibility outward in a generally transverse direction than saidfirst portion of said quarter.
 2. An absorbent article for wearing in awearer's undergarment, said absorbent article having a principallongitudinal centerline that is oriented in a longitudinal direction,and a principal transverse centerline that is oriented in a transversedirection, said absorbent article comprising:a main body portion havingtwo spaced apart longitudinal edges, two spaced apart transverse edges,a first end region, second end region, and a central region disposedbetween said end regions, said main body portion comprising a liquidpervious topsheet, a liquid impervious backsheet joined to saidtopsheet, and an absorbent core positioned between said topsheet andsaid backsheet; a pair of flaps for folding under the wearer'sundergarment, one of each of said flaps being joined to said main bodyportion at a juncture and extending laterally outward from one of saidlongitudinal edges beyond an outermost peripheral portion of said mainbody portion to a distal edge, said flaps being divided into a fronthalf and a back half by a flap transverse centerline that passes throughsaid central region of said main body portion, two corner regions ateach flap, said corner regions being located adjacent the juncture ofeach flap with said main body portion and comprising at least portionsof said flaps, wherein at least a portion of one of said corner regionsis located in the front half of said flaps and at least a portion of theother corner region is located on the back half of said flaps, and saidcorner regions are spaced longitudinally away from said flap transversecenterline, said absorbent article further comprising:a first portion ofsaid absorbent article disposed longitudinally inboard of each cornerregion, each said first portion being complementary with its respectivecorner region, wherein at least part of each said first portion isdisposed along said flap transverse centerline; and a non-elasticatedzone of differential extensibility in at least one of said cornerregions, said zone of differential extensibility having a greater rangeof extensibility outward in a generally transverse direction than saidfirst portions of said absorbent article.
 3. The absorbent article ofclaims 1 or 2 wherein said zone of differential extensibility is locatedbetween the longitudinal side edge of the main body portion and thedistal edge of one of said flaps.
 4. The absorbent article of claims 1or 2 wherein said zone of differential extensibility comprises portionsof said absorbent article having pleats with generallylongitudinally-oriented fold lines.
 5. An absorbent article for wearingin a wearer's undergarment, said absorbent article having a body-facingside, a garment side, a principal longitudinal centerline and aprincipal transverse centerline, said absorbent article comprising:amain body portion having a length, two spaced apart longitudinal edges,two spaced apart transverse edges, a first end region, a second endregion, and a central region disposed between said end regions, said endregions extending outward along said principal longitudinal centerlinefrom said central region a distance of about 1/8 to about 1/3 the lengthof said main body portion, said main body portion comprising a liquidpervious topsheet, a liquid impervious backsheet joined to saidtopsheet, and an absorbent core positioned between said topsheet andsaid backsheet; a pair of flaps for folding under the wearer'sundergarment, each flap being joined to said main body portion at ajuncture and extending laterally outward from one of said longitudinaledges beyond an outermost peripheral portion of said main body portionto a distal edge, said flaps having a flap transverse centerline thatpasses through the central region of said main body portion; saidabsorbent article being provided with a pleat along said juncture of atleast one of said flaps, said pleat having folds formed by generallylongitudinally-oriented fold lines; and a flap pleat restraint locatedin the area of said flap transverse centerline for restraining saidpleat from unfolding in the area of said flap transverse centerlinewhile allowing said pleat to unfold at locations disposed longitudinallyaway from said flap transverse centerline.
 6. The absorbent article ofclaim 5 wherein said flap pleat restraint can be broken and said flapcontaining said pleats can be unfolded and at least some of said foldsforming said pleats are located between the longitudinal edge of themain body portion and the distal edge of said flap.
 7. The absorbentarticle of claims 1, 2, or 5 wherein said junctures are located at eachlongitudinal edge of said main body portion.
 8. The absorbent article ofclaims 1, 2, or 5 wherein at least a portion of each of said juncturesis located inboard of a longitudinal edge of said main body portion. 9.The absorbent article of claim 8 wherein said flaps comprise at leastone separate element that is joined to said main body portion.
 10. Theabsorbent article of claim 8 wherein said flaps each comprise a separateelement.
 11. The absorbent article of claim 9 wherein said at least oneseparate element is at least partially joined to the garment-facing sideof said main body portion.
 12. A sanitary napkin that is worn in andsecured to a wearer's panties, said panties having an underside andcurved leg openings, and said sanitary napkin having a body-facing side,a garment side, a principal longitudinal centerline and a principaltransverse centerline, said sanitary napkin comprising:a main bodyportion having a length, two spaced apart longitudinal edges, two spacedapart transverse edges, a first end region, a second end region, and acentral region disposed between said end regions, said end regionsextending outward along said principal longitudinal centerline from saidcentral region a distance of about 1/8 to about 1/3 the length of saidmain body portion, said main body portion comprising a liquid pervioustopsheet, a liquid impervious backsheet joined to said topsheet, and anabsorbent core positioned between said topsheet and said backsheet; apair of flaps for folding under and securing to the underside of thewearer's panties, said flaps having a garment side that corresponds tothe garment side of said sanitary napkin, said flaps being subjected tostresses when said flaps are folded under said panties, each flap beingjoined to said main body portion at a juncture and extending laterallyoutward from one of said longitudinal edges beyond an outermostperipheral portion of said main body portion, said flaps having a flaptransverse centerline, an area surrounding and containing said flaptransverse centerline, and comprising a fastener for attaching said flapto the underside of the wearer's panties, said fastener being disposedalong said flap transverse centerline on the garment side of said flaps;said sanitary napkin being provided with a pleat along said juncture ofat least one of said flaps, said pleat having folds formed by generallylongitudinally-oriented fold lines; and a flap pleat restraint locatedalong said flap transverse centerline for restraining said pleat fromunfolding in the area of said flap transverse centerline while allowingsaid pleat to unfold at locations disposed longitudinally away from saidflap transverse centerline to provide slack material in said flaps torelieve the stresses which tend to develop when said flaps are foldedaround said curved leg openings of said panties.
 13. An absorbentarticle having a liquid pervious body-facing side and a liquidimpervious garment side, said absorbent article comprising:a main bodyportion having a length, two spaced apart longitudinal side edges andtwo spaced apart end edges defining a peripheral portion of said mainbody portion, a first end region, a second end region, and a centralregion disposed between said end regions, said end regions extendingoutward from said central region about 1/8 to about 1/3 the length ofsaid main body portion, said main body portion comprising an absorbentcore positioned between said body-facing side and said garment side; apair of flaps extending laterally outward along one of the longitudinalside edges beyond an outermost peripheral portion of said main bodyportion to a distal edge, said flaps each having a flap transversecenterline that passes through said central region of said main bodyportion and points along said flap transverse centerline; and anon-elasticated zone of differential extensibility comprising at least aportion of at least one of said flaps that is spaced longitudinally awayfrom said flap transverse centerline, said zone of differentialextensibility having slack therein and a greater range of extensibilityoutward in a generally transverse direction than the points on saidflaps located along said flap transverse centerline.
 14. An absorbentarticle having a liquid pervious body-facing side, a liquid imperviousgarment side, a longitudinal centerline, and a transverse centerline,said sanitary napkin comprising:a main body portion having a length, twospaced apart longitudinal side edges and two spaced apart end edgesdefining a peripheral portion of said main body portion, a first endregion, a second end region, and a central region disposed between saidend regions, said end regions extending outward from said central regionabout 1/8 to about 1/3 the length of said main body portion, said mainbody portion comprising an absorbent core positioned between saidbody-facing side and said garment side; a pair of flaps, each flapextending laterally outward along one of the longitudinal side edgesbeyond an outermost peripheral portion of said main body portion to adistal edge, said flaps each having a flap transverse centerline thatpasses through said central region of said main body portion and pointsalong said flap transverse centerline; and a non-elasticated zone ofdifferential extensibility comprising at least a portion of at least oneof said flaps that is spaced longitudinally away from said flaptransverse centerline, said zone of differential extensibilitycomprising material that has a greater range of extensibility outward ina generally transverse direction than the points on said flaps locatedalong said flap transverse centerline.
 15. An absorbent article having aliquid pervious body-facing side, a liquid impervious garment side, aprincipal longitudinal centerline, and a principal transversecenterline, said absorbent article comprising:a main body portion havinga length, two spaced apart longitudinal side edges and two spaced apartend edges defining a peripheral portion of said main body portion, afirst end region, a second end region, and a central region disposedbetween said end regions, said end regions extending outward from saidcentral region about 1/8 to about 1/3 the length of said main bodyportion, said main body portion comprising an absorbent core positionedbetween said body-facing side and said garment side; a pair of flaps,each flap extending laterally outward along one of said longitudinalside edges beyond an outermost peripheral portion of said main bodyportion to a distal edge, said flaps each having a flap transversecenterline that passes through said central region of said main bodyportion, first portions located along said flap transverse centerlineand spaced a distance outward from said principal longitudinalcenterline, and second portions spaced longitudinally away from saidflap transverse centerline the same distance outward as said firstportions; and a non-elasticated zone of differential extensibilitycomprising said second portions of said flaps, said zone of differentialextensibility comprising material that has a greater range ofextensibility outward in a generally transverse direction than the firstportions of said flaps.
 16. The absorbent article of claims 13, 14, or15 wherein said flaps are integral with said main body portion.
 17. Theabsorbent article of claims 13, 14, or 15 wherein said flaps are formedby at least one of said topsheet and said backsheet.
 18. The absorbentarticle of claims 13, 14, or 15 wherein said flaps comprise at least oneseparate element that is joined to said main body portion.
 19. Theabsorbent article of claim 18 wherein said flaps each comprise aseparate element.
 20. The absorbent article of claim 18 wherein said atleast one separate element is at least partially joined to thegarment-facing side of said main body portion.
 21. The absorbent articleof claim 20 wherein said at least one separate element is joined to thegarment-facing side of said main body portion at two junctures whereinone juncture is located at each longitudinal edge of said main bodyportion.
 22. The absorbent article of claim 20 wherein said at least oneseparate element is joined to the garment-facing side of said main bodyportion at two junctures, wherein at least a portion of each juncturelies inboard of each longitudinal edge of said main body portion.
 23. Anabsorbent article for wearing in a wearer's undergarment, said absorbentarticle having a principal longitudinal centerline that is oriented in alongitudinal direction, and a principal transverse centerline that isoriented in a transverse direction, said absorbent article comprising:amain body portion having two spaced apart longitudinal edges, two spacedapart transverse edges, a first end region, a second end region, and acentral region disposed between said end regions, said main body portioncomprising a liquid pervious topsheet, a liquid impervious backsheetjoined to said topsheet, and an absorbent core positioned between saidtopsheet and said backsheet; a pair of flaps for folding under thewearer's undergarment, said flaps being integral with said main bodyportion, one of said flaps extending laterally outward from each saidlongitudinal edge of said main body portion beyond an outermostperipheral portion of said main body portion, said flaps having a flaptransverse centerline that passes through said central region of saidmain body portion, and having portions of said flaps that are locatedalong said flap transverse centerline, wherein;said portions of saidflaps that are located along said flap transverse centerline lietransversely outboard of the longitudinal side edges of said main bodyportion when said flaps are extended, and said flap transversecenterline intersecting the principal longitudinal centerline of theabsorbent article and dividing the absorbent article into four quarters,each quarter comprising:a first portion of each quarter adjacent saidprincipal longitudinal centerline and said flap transverse centerline,and a second portion of each quarter outboard of said first portion ofeach quarter, said second portion of at least one of said quarterscomprising a non-elasticated zone of differential extensibility, saidzone of differential extensibility having a greater range ofextensibility outward in a generally transverse direction than saidfirst portion of said quarter.
 24. An absorbent article for wearing in awearer's undergarment, said absorbent article having a principallongitudinal centerline that is oriented in a longitudinal direction,and a principal transverse centerline that is oriented in a transversedirection, said absorbent article comprising:a main body portion havingtwo spaced apart longitudinal edges, two spaced apart transverse edges,a first end region, a second end region, and a central region disposedbetween said end regions, said main body portion comprising a liquidpervious topsheet, a liquid impervious backsheet joined to saidtopsheet, and an absorbent core positioned between said topsheet andsaid backsheet; a pair of flaps for folding under the wearer'sundergarment, said flaps being integral with said main body portion, oneof said flaps extending laterally outward from each said longitudinaledge of said main body portion beyond an outermost peripheral portion ofsaid main body portion to a distal edge, said flaps being divided into afront half and a back half by a flap transverse centerline that passesthrough said central region of said main body portion; and two cornerregions at each flap, said corner regions being located adjacent thejuncture of each flap with said main body portion and comprising atleast portions of said flaps, wherein at least a portion of one of saidcorner regions is located in the front half of said flaps and at least aportion of the other corner region is located on the back half of saidflaps, and said corner regions are spaced longitudinally away from saidflap transverse centerline, said absorbent article further comprising:afirst portion of said absorbent article disposed longitudinally inboardof each corner region, each said first portion being complementary withits respective corner region, wherein at least part of each said firstportion is disposed along said flap transverse centerline; and anon-elasticated zone of differential extensibility in at least one ofsaid corner regions, said zone of differential extensibility having agreater range of extensibility outward in a generally transversedirection than said first portions of said absorbent article.